The proposed experiments are designed to help us better understand the functional anatomy of the spinal micturition center and the physiologic mechanism of sphincteric relaxation. The specific aims for this project are: 1. To map the functional topography of the spinal cord relevant to induction of micturition 2. To study responses to stimulation of individual rootlets of the ventral component of sacral nerves. 3. To investigate the detailed functional anatomy and histochemistry of the genitourinary diaphragm and external urethral sphincter. 4. To investigate the role of non-adrenergic non-cholinergic (NANC) neurotransmission in urethral relaxation. 5. To explore possibilities of bladder reinnervation by direct nerve reimplantation into the bladder wall We will incorporate experience and data gained from preliminary studies into the current studies. By utilizing microstimulation, nerve-tracing techniques and computer technology, we will explore the topography of the spinal micturition center, establish stimulation techniques allowing selective stimulation of the motor nuclei of the bladder, the urethral sphincter and the pelvic floor and the functional anatomy of microstimulation. We will investigate selective rootlet stimulation in inducing selective responses in the bladder. We will also explore the neuropharmacology of urethral relaxation by studying NO-releasing substances (the neurotransmitter of the NANC neurotransmission) which are responsible for relaxation of urethral sphincter muscle. We are including extensive electron microscopic, neurohistochemical and electrophysical studies to better our understanding of the ultrastructure of the striated urethral sphincter and the innervation of the bladder.